What is a Beef Knuckle Bone?

A beef knuckle bone, also known as a stock bone or soup bone, is the joint connecting the cow’s femur to the tibia in the hind leg. It is one of the bones leftover after the butchering process when all the meat has been removed. Knuckle bones are incredibly useful for making bone broth, soup stocks, dog treats and other recipes.

Anatomy of a Knuckle Bone

The knuckle bone consists of the distal end of the femur bone and proximal end of the tibia bone. It forms the knee joint of the hind leg. The two rounded condyles at the end of the femur fit into the tibial plateaus of the tibia bone.

This allows the joint to flex and rotate. The whole structure is held together with cartilage, tendons and ligaments. When cooked, these connective tissues break down into gelatin which gives the bone its nutritional value.

Where Knuckle Bones Come From on the Cow

Knuckle bones come from the hind legs of beef cattle. There are two knuckle bones per cow, one on each hind leg. They connect the thigh bone (femur) to the shin bone (tibia).

On a standing cow, the knuckle joints are located right above the hock. This allows the cow to bend its legs at the knee. The knuckle bones bear much of the weight of the rear half of the cow.

Why Knuckle Bones are Left After Butchering

When a side of beef is broken down into subprimals, the knuckle bones are removed along with the flank and sirloin tip. The meaty portions are fabricated into cuts like tri-tip, flap meat, sirloin tip roasts and cubed steak.

Very little edible meat remains attached to the knuckle joint itself. The bones are too small and irregularly shaped to yield usable marrow as well. For these reasons, knuckle bones are typically left over after butchering.

Characteristics of Knuckle Bones

• Irregular, rounded shape with two distinct joints
• Single bone or two bones still connected
• Can be 3-6 inches long
• Weigh 0.5 – 1.5 lbs each
• Extremely hard, dense bone
• Contains cartilage, tendons and connective tissue
• Hollow center cavity in each condyle
• Very little meat or fat remaining

Nutritional Value of Knuckle Bones

The nutritional value of knuckle bones comes from:

• Collagen – Abundant collagen protein from cartilage, tendons and ligaments
• Gelatin – When cooked, collagen breaks down into gelatin
• Glycine – An amino acid that gives gelatin its unique health benefits
• Minerals – Rich source of calcium, phosphorus, magnesium and potassium

Unlike muscle meat, knuckle bones provide protein and minerals in a highly bioavailable matrix that is soothing and easily digested.

Uses for Beef Knuckle Bones

Bone Broth

The most common use of knuckle bones is for making beef bone broth. When simmered for extended periods, knuckle bones release their collagen, minerals and nutrients into the water. This creates a nourishing, gelatinous broth perfect for soups, stews and health drinks.

Soup Stock

Knuckle bones can be used alone or along with other bones (like marrow bones, oxtails and neck bones) to make a soup stock. Their heavy cartilage content gives the stock more body and thickness. The gelatin helps bind and emulsify the broth.

Dog Treats/Chews

The hollow marrow cavities and hard, dense bone make knuckle bones ideal long-lasting chews for dogs. Chewing helps clean dog’s teeth. Only feed cooked knuckle bones to avoid any splintering risk. Never feed them to aggressive chewers.

Gelatin Extraction

The abundant collagen in knuckle bones can be directly extracted into gelatin. Simply simmer, strain and chill the broth to collect the concentrated gelatin. Use this to make jello, gummies or health supplements.

Simmered Dishes

Add knuckle bones while braising tough cuts like brisket, shanks and short ribs. The connective tissue melts into the sauce creating more unctuous, finger-licking flavor.

Buying Knuckle Bones

Where to Buy

Knuckle bones can be purchased:

• Direct from local ranches/butcher shops
• Online grass-fed beef retailers
• Smaller co-ops and specialty grocers
• Ethnic markets – Latino, Asian, Indian
• Direct from producers at farmers markets

What to Look For

• Bones should have some cartilage and tissue remaining
• Minimal visible meat or fat
• Clean cut ends, not splintered
• Little to no blood remaining
• Fresh, mild smell – no strong odor
• Sold frozen or refrigerated – not sitting out

Cost

Expect to pay around $1.50 – $2.50 per pound for knuckle bones. Buying in bulk 10+ lbs at a time can save money. Bones can also sometimes be requested for free from butcher shops.

How to Cook Knuckle Bones

For Bone Broth

• Place bones in a pot and cover with water by 2-3 inches
• Bring to a boil then reduce to gentle simmer
• Skim any impurities as they rise
• Simmer for 24 hours up to 72 hours
• Strain, chill and skim fat before using broth

For Soup Stock

• Roast bones at 400°F for 30 mins to improve flavor
• Simmer roasted bones for 6-24 hours with veggies
• Strain out bones and vegetables before using stock

For Dog Treats

• Simmer bones until soft, about 1 hour
• Cool and refrigerate until firm
• Cut away any remaining soft tissue
• Slice bones into chunks using a cleaver

Health Benefits of Knuckle Bone Broth

Drinking bone broth made from knuckle bones provides:

• Bioavailable minerals – calcium, magnesium, phosphorus, potassium
• Collagen protein helps seal leaky gut
• Glycine boosts glutathione antioxidant levels
• Chondroitin and glucosamine for joint health
• Hydration and electrolytes from mineral content
• Anti-inflammatory and immunity benefits

Storage and Shelf Life

Store knuckle bones frozen at 0°F if not using immediately. They can be kept frozen for 6-12 months without losing any nutritional value.

Once cooked into bone broth or soup stock, the shelf life in the fridge is 5-7 days. The broth can also be frozen for 4-6 months.

Key Takeaways

• Knuckle bones are the femur-to-tibia joint in a cow’s hind legs
• They contain collagen-rich cartilage, tendons and ligaments
• Knuckle bones are left over after removing meat during butchering
• Prized for making bone broth, soup stocks and dog treats
• Rich in protein, minerals and joint-healthy compounds
• Simmering releases gelatin, collagen and nutrients into the water
• Provides more bioavailable nutrition than muscle meat
• Look for quality bones from grass-fed/organic sources
• Cook for 24-72 hours to fully extract the benefits
• Versatile ingredient to create nourishing, mineral-rich dishes